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An optimization procedure for the design of freely suspended exterior hoods in industrial ventilation systems was described. Theoretical considerations in the investigation of the implications of hood orifice geometry and in the selection of proper size of the orifice were addressed. An experimental study was carried out to verify the theoretical calculations indirectly. Three oblong hoods were constructed. With hood openings fixed, conditions under which the hoods were optimum were calculated for different values of frontal distance. The optimum flow rate was then predicted for each condition. The air speed was measured at each theoretically determined specification point and the flow rate was adjusted until the air speed specification was fulfilled. The experimentally determined flow rate was then compared to the theoretical flow rate. The authors conclude that the optimization procedure appears to be satisfactory and perhaps slightly pessimistic in the indication of the flow rate required. Hoods designed using the described process should have a superior total efficiency as compared to traditionally designed hoods.